whats up guys, sorry if this is a noob question

i think i'm going to replace my headers on my em1 ..
right now i'm running dc sports, but they were on from the previous owner
and i want to change them b/c theres rust and a small whole from bottoming out

thing is, i think i have to change the cat, so i was going to do that as well
but the headers i was looking at have a 2.5 collector, and said cat would need slight modification ..
does that mean i need to run an aftermarket catalytic converter ?
and if i use a cheap one from ebay, will it still allow me to pass emissions ?


any help's appreciated ..

 

Please say headER. I'd find a "kit" with header, downpipe, and catalytic converter.

 

I forget the company, you could probably find it if you searched (that's how I came across it), but they make an aftermarket ITR header. Get that, and a used CTR/ITR catalytic.